This invention relates generally to wiping and specifically to wiping of rear view mirrors of vehicles such as trucks, buses, and similar vehicles and to adjustment of mirrors.
The use of wipers on the exterior rear view mirrors of large commercial vehicles is a potential trend in the industry. Because of their length, it is especially important that trucks and buses have an excellent view of what is beside them. Unfortunately, heavy rainfall can obscure the view in a standard rear view mirror. Even a heated mirror does not help in heavy rainfall. If a dangerous circumstance suddenly presents itself in a vehicle""s path, the driver might not be able to tell whether it is safe to change lanes, left or right, to avoid the danger. Therefore, having clean mirrors can prevent accidents and save lives.
Patents have been issued on various inventions related to wiping of exterior rear view mirrors. For example, U.S. Pat. No. 4,459,718 to Hewitt et al. describes a fluid pressure operated reciprocating mechanism which vertically wipes a rear view mirror. U.S. Pat. No. 4,672,708 to Williams describes a mirror wiper assembly with manually operated remote control, where operation of the remote control causes the wiper arm to move through one complete cycle. U.S. Pat. No. 5,522,112 to Tiffany, III describes a wiping mirror assembly driven by a screwelement which causes the wiper to vertically traverse the mirror. Two notable patents, U.S. Pat. No. 5,179,758 and U.S. Pat. No. 5,353,466, assigned to the assignee of the present application address some of the problems in the industry and are incorporated herein by reference.
Despite the existence of the above-noted patents there still remains inherent problems in the prior art. Specifically, convex mirrors (fish-eye mirrors) are often attached to the flat surface of the rearview mirror to provide better viewing range. However, since the prior art incorporates the use of straight wiper blades, the convex mirror attachment inhibits the use of such wiper blades to wipe both the flat and convex surfaces of the mirrors.
Another problem in the art relates to the mechanism for reversing direction of the wiper blade, i.e., the use of pairs of electrical contacts located at the extreme ends of the mirror. The pairs of electrical contacts are generally used to signal the device that drives the wiper arm when the wiper blade has reached the extreme end so that the direction of the blade can then be reversed. However, by using these pairs of contacts, the electrical system becomes more complex and subject to an increased failure rate should there be a problem with the contacts, such as corrosion, debris, or the like.
Furthermore, despite the issuance of the patents on the various inventions related to wiping of rearview mirrors, it is still a rare sight to see a vehicle equipped with any of these inventions. In the absence of regulations mandating wipers on the external rear view mirrors of large commercial vehicles, the popularity and commercial success of such wipers can be expected to be highly price sensitive.
An exterior rearview mirror assembly is provided for use on a vehicle which includes a rearview mirror and a wiper assembly. The wiper assembly includes a wiper arm base located behind the mirror assembly extending over the top of the mirror to attach to a resilient wiper arm having a wiper blade. The wiper blade is shaped or sectioned to substantially mate with mirrors having uneven surfaces such as when a convex mirror is attached to the flat surface of the rear view mirror. The wiper arm base is preferably attached to a bi-directional driver system which causes the wiper arm base to laterally transverse across the mirror assembly, which in turn drives the wiper blade across the mirror. The bi-directional driver system preferably includes a uni-directional belt system, about two pulleys, connected to the wiper arm base with a unique linkage to allow the base to traverse back and forth as the belt is driven about the pulleys. In another embodiment, a bi-directional system is utilized where the direction of a pulley or other drive means is changed by a centrally located switch activated by the traveling wiper.
In one embodiment, the bi-directional driver system preferably includes a uni-directional belt system, about two pulleys. The pulley system comprises two oppositely spaced pulleys and a belt. The pulleys are located on the backside said mirror sufficiently far apart to allow the wiper blade to traverse the mirror surface, with the belt being affixed around the pulleys. The pulley system is driven by a uni-directional motor which is attached to either pulley with a drive belt. The belt necessarily rotates about the pulleys such that the belt portion on the upper turn of the pulley system travels in one direction and the belt portion on the lower turn of the pulley system travels in the opposite direction. The wiper arm base is connected to the pulley system with a unique linkage to allow the base to traverse back and forth following the upper and lower directions of the belt about the pulleys. Alternatively, the pulleys and belt can be replaced with a chain and gears.
In an alternative embodiment, the mirror assembly comprises at least one spirally threaded rod inserted through a counter-threaded hole within the wiper arm base. The threaded rod meshes into a worm gear meshed to a worm of driver thereby translating bi-directional rotation to the threaded rod, causing the wiper arm base to traverse across the mirror surface.
In another embodiment, the mirror assembly comprises a pulley assembly to which the wiper arm base is securely attached. At least one rod is inserted through the wiper arm base to maintain the wiper arm base along a straight path. The pulley system provides the lateral movement, causing the wiper arm base to traverse across the mirror surface
In the two above embodiments, a switch is centrally located near the rods. The switch is affixed to the wiper arm base such that the DPDT switch is activated when the wiper arm base reaches either end of the rod. The activation of the switch causes the motor to reverse direction of the wiper arm base, periodically causing the blade to traverse back and forth across said flat outer surface in a wiping manner.